Induced Current Distribution in 3D Soil Model as Lightning Impulse Discharge Strike Earth Surface

Presented in this paper is the numerical solution to the current distributions on two forms of Yagi-Uda antenna designs. One form consists of twelve elements while the other consists of fourteen elements. Employing method of moments technique in which the unknown current is expanded in terms of known expansion function and complex coefficients which are to be determined. It is demonstrated that, when the integral equation that expresses tangential component of an impressed field in terms of induced current on the elements of Yagi-Uda array is reduced into matrix form, the current distribution of interest becomes known. The profiles for the current distributions on elements of those arrays represented in graphical forms reveal that, the currents are symmetrical about the length of the element in each case. It is found that the highest magnitude of the current exists on the driven element. Furthermore, the characteristic profiles of the currents on elements of those arrays exhibit sinusoidal type of waveform and are largely similar when the frequencies of operation are 200MHz and 665MHz, respectively.

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Transient lightning response to grounding grids buried in horizontal multilayered earth model considering time domain quasi-static complex image method and soil ionization effect

COMPEL The International Journal for Computation and Mathematics in Electrical and Electronic Engineering ◽

10.1108/compel-11-2020-0388 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Zhong-Xin Li ◽

Peng Li ◽

Ke-Chao Wang

Keyword(s):

Impulse Response ◽

Current Distribution ◽

Time Domain ◽

Earth Model ◽

Content Type ◽

Lightning Current ◽

Ionization Effect ◽

Lightning Impulse ◽

Grounding Grids ◽

Soil Ionization

Purpose The purpose of this paper is to propose a fast, accurate and efficient algorithm for assessment of transient behavior of grounding grids buried in horizontal multilayered earth model considering soil ionization effect. Design/methodology/approach The purpose of this paper is to develop a numerical simulation method to calculate the lightning impulse response of the grounding grid buried in a horizontal multilayered earth model. The mathematical model about the hybrid method based on PI basic function belonging to time domain is proposed in the paper; the mode can precisely calculate the lightning current distribution and lightning impulse response to grounding grids buried in horizontal multilayered soil model considering soil ionization effect. To increase computing efficiency, quasi-static complex image method (QSCIM) and its time-domain Green’s function closed form are introduced in the model. Findings The hybrid model is rather stable, with the respect to the number of elements used and with excellent convergence rate. In addition, because this mathematical model belongs to the time domain algorithm, it is very powerful for the simulation of soil ionization caused by high amplitude lightning current. Research limitations/implications To increase computing efficiency, QSCIM and its time domain Green's function closed form are introduced in the model. Practical implications The mathematical model about the hybrid method based on PI basic function can precisely calculate the lightning current distribution and lightning impulse response to grounding grids buried in horizontal multilayered soil model considering the soil ionization effect. Social implications Considering the soil ionization effect, the simulation calculation of lightning impulse response of substation grounding grid buried in the actual horizontal multilayered earth can effectively support the scientific and efficient design of lightning protection performance of substation grounding grid. Originality/value The hybrid model in time domain is originally developed by the authors and used to precisely calculate the lightning current distribution and lightning impulse response to grounding grids buried in horizontal multilayered soil model considering soil ionization effect. It is simple and very efficient and can easily be extended to arbitrary grounding configurations.

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